Xu Xiake (1587-1641) -- The Art of Travel Writing; Ward, Julian (University of Edinburgh)
XENIX Command Reference Guide Most Important Commands -- What They Are, How They Work and How to Use Them; Christian, K. (Rockefeller University, USA);Richter, S. (The Rand Corporation, Santa Monica, California, USA)
Xenophon and the History of His Times -- Dillery, John (University of Michigan, USA)
X-Linked Mental Retardation -- Stevenson, Roger E. / Joint Author Schroer, Richard J. / Joint Author Schwartz, Charles E.